Brake



June 13, 1944. J. G. HAWLEY BRAKE '2 sheets-sheet `1 Filed Sept. 5, 1940 @mw @EN @QN NNN .Lr -bwa me/Wto@ @SSG G-Hawlcg,

Julie i3, Q HAWLEY BRAKE Filed Sept. 5, 1940 2 Sheets-Sheet 2 .sse awlety,

, eted to a flange I4 on wheel hub I5. v units are preferably carried, as described here- Patented June 13, 1944 lUNITED sTATEs PATENT OFFICE 2.351.041 muxa Jene G. Hawley, Painted Post, N. Y. Application September 3, 1940, Serial No. 355,263 s claim. (ci. 18s-152) This invention relates to the art of brakes, and more particularly to a hydraulic brake which is especially useful for airplanes.

Most airplane brakes which have heretofore been developed have been cumbersome and heavy, or have been of complicated construction.

I have found that these disadvantages can be overcome, and a vhighly effective brake, particularly useful for airplanes, can be produced by the construction disclosed herein.

lowing speciilcation and have illustrated it in the accompanying drawings. in which:

Figure 1 is a vertical lonigtudinal section showing' my new brakes applied to an airplane wheel;

Fig. 2 is a vertical transverse section, on an enlarged scale, on the line 2-2 of Fig. 1; and

Fig. 3 is a vertical longitudinal section through the upper power unit brake shown in Figs. 1 and 2.

Referring to the accompanying drawings, and more particularly to Fig. 1 thereof, my new brake III comprises one or more power units 20, which will berdescribed in detail hereinafter, one or more brake clamps I I provided with brake lining I2, I2', and a braking disc I3. The latter is preferably a circular di'sc that is screwed or riv- Power inafter, by abracket I6 which is bolted to a ange I1 welded, or otherwise secured, to the axle I8. v

'I'he operating mechanism for my new brake comprises one or more of the power units 20,

which are preferably of the type disclosed and claimed in my co-pending application Serial No. 337,102, filed May 24, 1940. This preferably comprises a fluid cylinder 2|, a' piston cylinder 22, a resilient seal 23, a piston 24, and a piston rod 25.

As -best shown in Fig. 3, fluid cylinder 2| and piston cylinder 22 are cup-shaped members terminating in circumferential anges 26 and 21,

l respectively, between which a flange 28 on the resilient seal 23 aud a spacer ring 30 are securely held by a clamping ring 3|. which is securely clamped therearoundby any convenient means,

as a power press (not shown).

Resilient seal 23 is preformed and is resistant to oils. It is made of any suitable material, such as neoprene, buna rubber, or thiokol. As shown, it comprises a bottom portion 32 which is at, side wall 33 at right angles thereto, and the aforementioned flange 26 which extends at right angles to the side wall 33 and terminates in a secondary flange 34 that is parallel to the side.

wall 33 but spaced therefrom.l

The piston 24 comprises a head 35 and a circumferential Vflange 36 at right angles thereto. The head and flange 36 are made just vsufficiently smaller than the resilient seal 23 to permit the piston 24 .to be inserted in the resilient seal without deforming it, and the internal diameter of the spacer ring 30 is only sumciently,l

larger than the diameter of they piston 24 to permit its moving freely therethrough.

Piston cylinder 22 comprises a bottom portion 31, which is fiat but is provided with an orifice 38, for a purpose to be described later, and a side wall 40, whose internal diameter is equal to the internal diameter of the side wall 33 of resilient seal 23, and which is only suiliciently larger than the external diam'eter qof the flange 36 on piston 24 to permit it to 'i'nove freely therethrough.

Side wall 40 terminates in the flange 2l described above, and this, in turn, is provided with a right angular extension 4 I, which is parallel to the side wall 40 and of a suitable internal diameter such that it just accommodates spacer ring 30 and flange 34 of resilient seal 23.

Fuild cylinder 2I comprises a bottom portion 42 provided with a side wall 43 that is of just sulcient internal diameter to allow the side wall 33 of resilient seal 23 to fit therein without deformation. Side wall 43 terminates in flange 26 discussed above.

Bottom portion 42 is provided with two bosses 50, 54 'thatl are preferably formed integral therewith. Boss is internally threaded at 5I to receive any suitable coupling (not shown), and is provided with an orifice 52 to permit uld (not shown) to enter a chamber 53 formed in fluid cylinder 2i between its bottom portion 42 and the resilient seal 23. Boss 54 is preferably internally threaded to receive a correspondingly threaded bleeder plug 55, provided with a square head 56. Bleeder plug 55 communicates with the exterior through a longitudinal orice (not shown) that communicates with a transverse orice 51, in a shank 58 of reduced diameter.

Orifice 51 can communicate with a transverse orifice 80 in bottom portion 42 of fluid cylinder 2|, and thence with the chamber Il when the bleeder plug 55 is partially unscrewed from its seat 6I. This may conveniently be done with a screw driver by inserting the latter in a transverse slot 82 in the head of the bleeder plug Il.

Piston rod 25 is provided with a fiat head 10 and a tapered end .'I I. Piston rod 2B operates in, and is guided by, a power head 1t that has a longitudinal aperture 11 of just suiiiciently larger internal diameter than piston rod '2l to allow the latter to move therein without undue friction. Power head 16 is preferably a screw machine part that is externally threaded at 10.

'I'he travel of piston rod 25 is preferably controlled by a spacer 04, provided with an external flange 85, whose external diameter corresponds to the internal diameter of the side wall 40 of piston cylinder 22, and with anoriilce 2l that is of large enough diameter to permit the piston rod 25 to move therethrough without undue friction. A spacer sleeve 81, that is of sufllciently smaller external diameter to ilt snugly in spacer 04, and of larger internal diameter than the orifice 06. is designed to retain a stop pin l,

, carried by the piston rod 25 but projecting therebeyond, so as to limit the travel of the piston rod 25 between the spacer 04 and the linner end of power head 16. Spacer sleeve l1 is preferably separate from the threaded portion of power head 16. Spacer 24 is also internally threaded to engage the inner threaded end 1l of power head 16.

A heavycoil spring 00 is telescoped around spacer 04, and bears against the flange 8l thereof and vagainst the head 10 of piston rod 25, to normally force the latter into engagement with piston 24 and cause that to bear against resilient bottom portion 22 of resilient seal 23, but spring 90 is of insuillcient power to stretch the resilient seal. The latter is free of either compression or distention when it is'in normal position.

With the construction described, when it is -desired to apply the brake, the operator. supplies actuating fluid to the power unit 20 by moving a lever or pressing a button (not shown) which causes fluid from any suitable outside source (not shown) to enter chamber. il in iiuid cylinder 2I, through the oriilce 52 and bear against the exposed portion 32 of resilient seal 23. This moves piston 24 and piston rod 2l forward against the pressure of spring 90 and forces the tapered end 1I of piston rod 25 outwardly into contact with a pressure block Il l which is interposed between the piston rod and the inner Y most brake lining I2, thus forcing the latter into contact with the braking disc I3. This action simultaneously pulls the outer brake lining I2', carried by the outer portion of the brake clamp II, into contact with the opposite side of the braking disc I3 to complete the brake application.

As best shown in Fig. 3, brake clamps II each have a threaded longitudinal recess |0I to cooperate with the threads 10 on power head 10 and an enlarged recess |02 to receive and guide the pressure block |00 and brake lining I2. They are also provided with an-entrance slot |03 (FIS. 1) to accommodate the braking disc I3 and brake lining I2'. The latter is secured to the outer end |04 of the clamp in any desired way. as by rivets |09 (Fig. 2).

Each clamp II is also provided with Aan arm |05 that is apertured at IINvl to receive a stud I01. The latter is provided with a transverse orifice to receive a pin |08 by which it is detachably secured to the bracket Il. At its opposite end, stud |01 is provided with a cross pin |I0 to retain a pair of washers III and a spring II2 which are adapted to give the clamp a slight yielding .movement during the braking action. Each clamp Il is provided with a plurality of reinforcing ribs IIB.

As shown in Fig. l, the axle Il is supported in the wheel hub I5 by a pair of Timken bearings I20, each of which is retained inposition by a washer assembly comprising a felt washer I2l protected by metal washers |22 and |22 and a spring retaining ring |24 which is received in a recess |25 in the wheel hub I5.

At -its outer end, axle Il is provided with threads |26 to receive a retaining nut |21.

A tire |30 is mounted on the wheel hub It and is retained thereon between flange ISI on the inner side of the hub and a retaining flange II2 on the outer side 4of thehub. The latter is retained in position by a spring retaining ring |33 which is received in registering recesses |24 and |35 in the wheel hub I6 and retaining flange |32, respectively.

A light metal hub cap Ill is spring held in the retaining flange II2 to prevent the entrance of dirt and moisture.

The parts of my brake construction and related mechanism may be made of any desired materials. In general, however. I prefer to make the braking disc of chromium plated carbon steel or stainless steel. For airplane use. the wheel hub is preferably of light weight material, such as aluminum or magnesium alloys of the Dow Metal type. The clamp is also preferably made of Dow Metal or Lynite. The brake lining may be of any desired material, such as the conventional asbestos brake lining, or of leather. The latter has been found to be particularly satisfactory.

While I have only shown two or my improved power units and related brake mechanisms in Fig. l, it will be understood that I may use one or any desired number of these power unit clamp brakes, and. by increasing the number, or by using umts of larger diameter, and by regulating the amount of operating fluid supplied to them, any desired braking pressure can be obtained. Furthermore. by a proper distribution of the power unit brakes around the periphery of the circular disc, a substantially equal pressure may be exerted around its entire periphery, and, by the use of proper springs II2, the braking thrust can be properly balanced. Also, in view of the simple construction of the parts shown, any broken or damaged unit may easily be replaced and a new unit substituted without disassembling A the wheel or the tire.

It will therefore be apparent that I have developed a new and useful brake which is capable of general application, but which is particularly adapted for airplane use. It is a particular point of my invention that my new brake construction departs from conventional types and uses one or more relatively small clamp brakes, which have braking surfaces of relatively small area, including my improved power units. The latter may be operated simultaneously by the use of a master cylinder, although this has not been shown in the drawings, since it forms no fpart of the present invention.

As many apparently widely diiferent embodiments of this invention may be made without de- 2,861,041 parting from the spirit thereof, it is understood 1. A brake, comprising a fixed support, an 1 open-jawedclamp of less than annular extent carried thereby, a friction imparting member loosely supported therein, an annular disc rotatable through the open jaw of the clamp, Iand a sealed hydraulic power unit for forcing the friction imparting member against the rotatable disc, the clamp and power unit being detachably connected to the fixed support through a springpressed stud and being removable from the fixed support without removing any other parts.

2. A brake, comprising a fixed support, a re.- movable open-jawed clamp carried thereby, a friction imparting member loosely supported therein, a disc rotatable through/the open jaw of the clamp, and a hydraulic power unit for forcing the friction imparting member against the rotatable disc, the clamp being lyieldingly mounted on the xed support and the rotatable disc being carried by a wheel hub.

3. In a brake construction, the combination of a wheel hub, an annular rotatable disc carried thereby, a fixed axle, and a brake arranged in cooprative relation thereto and supported thereby, the brake comprising an open-jawed clamp of less than annular ,extent through which the disc is movable, a friction imparting member car-l ried by the clamp adjacent to the surface of the disc, and a sealed power unit for forcing the friction imparting member against the disc, the clamp and power unit being detachably connected to the fixed axle through a spring-pressed stud and being removable from its support without removing any other parts.

4. An airplane brake, comprising a continuous circular disc carried by a wheel hub, a lxed support, a plurality of open-Jawed clamps carried thereby and through which the disc is successively movable, a pair of braking discs carried by each clamp,` one of which discs is adjacent to each surface of the circular disc, and a sealed power unit carried by each clamp for forcing thebraking discs into contact with the circular disc, each clamp and its power unit constituting a unitary member which is removable from the fixed support independently without disturbing the others.

5. A brake assembly, comprising a clamp, a rotary member for engagement with the clamp, and a sealed removable power unit for actuating the clamp, said power unit having a fluid cylinder, a piston cylinder, a cup-shaped resilient seal interposed between these two cylinders, a fluid inlet port, and means for sealing said .power unit against the entrance of any substance except through said fiuid inlet port.

:Essa G. HAWLEY. 

